feat: Add delivery status for Twilio Channel (#8082)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

spec/controllers/twilio/delivery_status_controller_spec.rb

@@ -0,0 +1,18 @@
+require 'rails_helper'
+
+RSpec.describe 'Twilio::DeliveryStatusController', type: :request do
+  include Rails.application.routes.url_helpers
+  let(:twilio_service) { instance_double(Twilio::DeliveryStatusService) }
+
+  before do
+    allow(Twilio::DeliveryStatusService).to receive(:new).and_return(twilio_service)
+    allow(twilio_service).to receive(:perform)
+  end
+
+  describe 'POST /twilio/delivery' do
+    it 'calls incoming message service' do
+      post twilio_delivery_status_index_url, params: {}
+      expect(twilio_service).to have_received(:perform)
+    end
+  end
+end